# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1178

[Latest](https://discourse.julialang.org/latest.md) · [Categories](https://discourse.julialang.org/categories.md) · [Tags](https://discourse.julialang.org/tags.md)

**Page:** 1179

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## [Habana Gaudi AI Processors - Julia support?](https://discourse.julialang.org/t/habana-gaudi-ai-processors-julia-support/73093)

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**Author:** [@anon28281882](https://discourse.julialang.org/u/anon28281882)\
**Replies:** 4\
**Last updated:** [December 15, 2021, 12:40am UTC](https://discourse.julialang.org/t/habana-gaudi-ai-processors-julia-support/73093 "2021-12-15T00:40:24Z")

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Hi, Do you think that there is any chance that Habana is going to support Julia on their processors in the future (https://developer.habana.ai/) or is it rather very unlikely?

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## [Disallow more subtypes](https://discourse.julialang.org/t/disallow-more-subtypes/73103)

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**Author:** [@jzr](https://discourse.julialang.org/u/jzr)\
**Replies:** 2\
**Last updated:** [December 15, 2021, 12:18am UTC](https://discourse.julialang.org/t/disallow-more-subtypes/73103 "2021-12-15T00:18:45Z")

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abstract type Foo end struct FooA \<: Foo x end struct FooB \<: Foo x end I want to disallow any other concrete types of Foo. Is that possible?

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## [MethodError: no method matching!](https://discourse.julialang.org/t/methoderror-no-method-matching/73098)

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**Author:** [@Sahar](https://discourse.julialang.org/u/Sahar)\
**Replies:** 2\
**Last updated:** [December 15, 2021, 12:01am UTC](https://discourse.julialang.org/t/methoderror-no-method-matching/73098 "2021-12-15T00:01:55Z")

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Hello to everyone, I am quite new to julia language and could you please help me to figure it out, why I get this error ? #Packages begin using Pkg PkgList = \["CSV", "DataFrames", "Ipopt", "JuMP", "Plots", "Pluto…

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## [Entropy maximization with nonlinear constraint](https://discourse.julialang.org/t/entropy-maximization-with-nonlinear-constraint/73104)

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**Author:** [@mvsoom](https://discourse.julialang.org/u/mvsoom)\
**Replies:** 4\
**Last updated:** [December 14, 2021, 11:55pm UTC](https://discourse.julialang.org/t/entropy-maximization-with-nonlinear-constraint/73104 "2021-12-14T23:55:50Z")

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I’m trying to solve the following entropy maximization problem: \\max\_p -\\sum\_{ij} p\_{ij} \\log p\_{ij} s.t. p \\in \\mathbb{R}^{n \\times n} \\\\ p\_{ij} = p\_{ji} \\\\ 0 \\leq p\_{ij} \\leq 1 ~ \\forall (i,j) \\\\ \\sum\_{ij} p\_{ij} …

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## [Mass matrices for cases of du/dt = f(du, u, p, t) where du and u are matrices?](https://discourse.julialang.org/t/mass-matrices-for-cases-of-du-dt-f-du-u-p-t-where-du-and-u-are-matrices/73094)

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**Author:** [@jqbond](https://discourse.julialang.org/u/jqbond)\
**Replies:** 2\
**Last updated:** [December 14, 2021, 11:53pm UTC](https://discourse.julialang.org/t/mass-matrices-for-cases-of-du-dt-f-du-u-p-t-where-du-and-u-are-matrices/73094 "2021-12-14T23:53:38Z")

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I wrote an ad hoc script for a method of lines problem where I discretized the spatial domain and used and ODE solver to integrate in the time domain. At the moment, I’m not interested in a discussion of whether this is …

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## [Pass Vector to @subset](https://discourse.julialang.org/t/pass-vector-to-subset/73099)

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**Author:** [@HiramTheHero](https://discourse.julialang.org/u/HiramTheHero)\
**Replies:** 2\
**Last updated:** [December 14, 2021, 11:31pm UTC](https://discourse.julialang.org/t/pass-vector-to-subset/73099 "2021-12-14T23:31:45Z")

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Long story short, how do I pass a vector to @subset. # From this... @subset(iris, VectorIPassToTheFunction) ) # To this... @subset(iris, :SepalLength .\> 6, :SepalWidth .\> 3) ) Long story: In the DataFramesMeta packag…

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## [How to kill a persistent REPL?](https://discourse.julialang.org/t/how-to-kill-a-persistent-repl/69813)

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**Author:** [@lrnv](https://discourse.julialang.org/u/lrnv)\
**Replies:** 8\
**Last updated:** [December 14, 2021, 10:54pm UTC](https://discourse.julialang.org/t/how-to-kill-a-persistent-repl/69813 "2021-12-14T22:54:52Z")

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Hi, I’m using the "julia.persistentSession.enabled": true option of the vs code extension. Its working great. The only thing is that the Julia: Stop REPL only closes the terminal but does not kill the julia instance. Fu…

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## [Generating a nice mesh on a sphere S^2](https://discourse.julialang.org/t/generating-a-nice-mesh-on-a-sphere-s-2/73075)

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**Author:** [@BVPs](https://discourse.julialang.org/u/BVPs)\
**Replies:** 8\
**Last updated:** [December 14, 2021, 10:52pm UTC](https://discourse.julialang.org/t/generating-a-nice-mesh-on-a-sphere-s-2/73075 "2021-12-14T22:52:42Z")

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I would like to generate a nice mesh/grid (i.e., as homogeneous/isotropic as possible) on the unit sphere S^2 in R^3. In particular, I would like to generate two possible grid systems: 1) based on triangles; or 2) based …

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## [Extending a Package (without forking)](https://discourse.julialang.org/t/extending-a-package-without-forking/73091)

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**Author:** [@gideonsimpson](https://discourse.julialang.org/u/gideonsimpson)\
**Replies:** 1\
**Last updated:** [December 14, 2021, 10:24pm UTC](https://discourse.julialang.org/t/extending-a-package-without-forking/73091 "2021-12-14T22:24:10Z")

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I have a package that I wrote which is part of the Julia package registry that I would like to extend in a nonstandard way. It’s organized in the same spirit as Optim.jl in the sense that there are a much of different s…

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## [Trying to use JLD.jl with Julia v1.7.0-beta3](https://discourse.julialang.org/t/trying-to-use-jld-jl-with-julia-v1-7-0-beta3/66017)

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**Author:** [@aaraujo71](https://discourse.julialang.org/u/aaraujo71)\
**Replies:** 8\
**Last updated:** [December 14, 2021, 8:29pm UTC](https://discourse.julialang.org/t/trying-to-use-jld-jl-with-julia-v1-7-0-beta3/66017 "2021-12-14T20:29:12Z")

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I need to save variables of different types in Julia, and I’ve tried JLD.jl in Julia v1.6.2 without any problem. However, since I’m using the new Mac M1, I moved to the new upcoming release v1.7.0-beta3 (and it’s really …

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## [Docker (julia:1.7.0-alpine3.15) with custom Python Enviroment](https://discourse.julialang.org/t/docker-julia-1-7-0-alpine3-15-with-custom-python-enviroment/73089)

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**Author:** [@Pytrator](https://discourse.julialang.org/u/Pytrator)\
**Replies:** 0\
**Last updated:** [December 14, 2021, 6:55pm UTC](https://discourse.julialang.org/t/docker-julia-1-7-0-alpine3-15-with-custom-python-enviroment/73089 "2021-12-14T18:55:41Z")

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Hey there, I am trying to create a Docker-Template for anyone who wants to run their projects in Docker/Apline with a custom Python Version. Currently, I´m getting this issue and I don’t know how to fix it. There are pl…

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## [Need help proofreading my BLSTM implementation](https://discourse.julialang.org/t/need-help-proofreading-my-blstm-implementation/73015)

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**Author:** [@Qfl3x](https://discourse.julialang.org/u/Qfl3x)\
**Replies:** 4\
**Last updated:** [December 14, 2021, 5:55pm UTC](https://discourse.julialang.org/t/need-help-proofreading-my-blstm-implementation/73015 "2021-12-14T17:55:40Z")

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Hi, I’m implementing a BLSTM for a personal (soon finished) project of mine and I’m currently very confused as to how BLSTM’s are implemented and found various kinds of implementations in papers online, mine should conca…

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## [Logical masking of gridded data](https://discourse.julialang.org/t/logical-masking-of-gridded-data/73082)

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**Author:** [@fran94](https://discourse.julialang.org/u/fran94)\
**Replies:** 2\
**Last updated:** [December 14, 2021, 5:50pm UTC](https://discourse.julialang.org/t/logical-masking-of-gridded-data/73082 "2021-12-14T17:50:21Z")

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Hi all, I have a regular grid of Nx \* Ny, over which I am computing some things. Now, I want to select a circle on it at location (Nx/4, Ny/2) with radius (Ny/4). I have tried the following: circle = @. \[((x - Nx/4)^2 …

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## [Computing left-eigenvectors with high precision](https://discourse.julialang.org/t/computing-left-eigenvectors-with-high-precision/72949)

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**Author:** [@yosuga](https://discourse.julialang.org/u/yosuga)\
**Replies:** 15\
**Last updated:** [December 14, 2021, 5:27pm UTC](https://discourse.julialang.org/t/computing-left-eigenvectors-with-high-precision/72949 "2021-12-14T17:27:32Z")

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I need to get left-eigenvectors of a general complex matrix H. Especially, I want to treat a large and ill-conditioned one. I know two ways under using LinearAlgebra: computing the right-eigenvectors of H'. computing…

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## [Create variable based on array](https://discourse.julialang.org/t/create-variable-based-on-array/73070)

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**Author:** [@ahmad88](https://discourse.julialang.org/u/ahmad88)\
**Replies:** 1\
**Last updated:** [December 14, 2021, 4:59pm UTC](https://discourse.julialang.org/t/create-variable-based-on-array/73070 "2021-12-14T16:59:43Z")

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I have a tuple that contains pairs and I want to create a variable based on these pairs as follows E = \[(1, 2), (10, 16), (18, 24), (32, 33), (12, 10), (19, 18), (31, 30), (17, 36)\] for (i,j) in E @variable(model,x\[i…

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## [Best way to plot or display historical and real time trajectory](https://discourse.julialang.org/t/best-way-to-plot-or-display-historical-and-real-time-trajectory/73084)

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**Author:** [@benibilme](https://discourse.julialang.org/u/benibilme)\
**Replies:** 0\
**Last updated:** [December 14, 2021, 4:52pm UTC](https://discourse.julialang.org/t/best-way-to-plot-or-display-historical-and-real-time-trajectory/73084 "2021-12-14T16:52:15Z")

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Hello, I want to display past and present vehicle trajectories which are coming as continuous streams. What will be best way to plot or display streaming trajectory on a map. I looking for capabilities similar to pyth…

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## [Finding Jacobian using automatic differentiation for a vector function](https://discourse.julialang.org/t/finding-jacobian-using-automatic-differentiation-for-a-vector-function/73078)

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**Author:** [@Elmo](https://discourse.julialang.org/u/Elmo)\
**Replies:** 3\
**Last updated:** [December 14, 2021, 4:32pm UTC](https://discourse.julialang.org/t/finding-jacobian-using-automatic-differentiation-for-a-vector-function/73078 "2021-12-14T16:32:13Z")

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Hi, I want to use automatic differentiation to calculate the Jacobian of vector functions. However, I am running into errors that I don’t know how to solve. Here is a minimal working example: using ForwardDiff using Rev…

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## [Square root of a matrix that has no square root](https://discourse.julialang.org/t/square-root-of-a-matrix-that-has-no-square-root/73081)

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**Author:** [@sijo](https://discourse.julialang.org/u/sijo)\
**Replies:** 3\
**Last updated:** [December 14, 2021, 4:01pm UTC](https://discourse.julialang.org/t/square-root-of-a-matrix-that-has-no-square-root/73081 "2021-12-14T16:01:22Z")

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Is this expected? julia\> sqrt(\[0 1; 0 0\]) 2×2 Matrix{Float64}: 0.0 0.0 0.0 0.0 I thought it would give an error.

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## [Ccall Fortran OpenBLAS multithreading issues with Julia 1.7](https://discourse.julialang.org/t/ccall-fortran-openblas-multithreading-issues-with-julia-1-7/72913)

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**Author:** [@Perrin\_Meyer](https://discourse.julialang.org/u/Perrin_Meyer)\
**Replies:** 7\
**Last updated:** [December 14, 2021, 4:06pm UTC](https://discourse.julialang.org/t/ccall-fortran-openblas-multithreading-issues-with-julia-1-7/72913 "2021-12-14T16:06:28Z")

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I am using Julia to drive a Fortran based Boundary Element code. The Fortran code uses OpenMP and OpenBLAS for multithreading. When I call into the BEM code from Julia 1.7, I now only get single-threaded performance. O…

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## [Specify interface methods to implement](https://discourse.julialang.org/t/specify-interface-methods-to-implement/73072)

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**Author:** [@HugoTrentesaux](https://discourse.julialang.org/u/HugoTrentesaux)\
**Replies:** 2\
**Last updated:** [December 14, 2021, 3:51pm UTC](https://discourse.julialang.org/t/specify-interface-methods-to-implement/73072 "2021-12-14T15:51:15Z")

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Is there a way (other than documentation) to define an interface in a way allowing to automatically check that a struct implements all required methods at compile time?

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## [ERROR: syntax: "\\" is not a unary operator](https://discourse.julialang.org/t/error-syntax-is-not-a-unary-operator/55854)

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**Author:** [@AngusRussell](https://discourse.julialang.org/u/AngusRussell)\
**Replies:** 8\
**Last updated:** [December 14, 2021, 2:47pm UTC](https://discourse.julialang.org/t/error-syntax-is-not-a-unary-operator/55854 "2021-12-14T14:47:45Z")

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I am currently working through the Introduction to Julia course and I am having trouble using the :smiley\_cat: syntax. When I try to assign a value to it in Jupyter lab and the repl I get the following error message: ER…

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## [Subplot of contours with different legends (Plots.jl; plotly backend)](https://discourse.julialang.org/t/subplot-of-contours-with-different-legends-plots-jl-plotly-backend/73076)

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**Author:** [@Fathya.Salih](https://discourse.julialang.org/u/Fathya.Salih)\
**Replies:** 0\
**Last updated:** [December 14, 2021, 2:35pm UTC](https://discourse.julialang.org/t/subplot-of-contours-with-different-legends-plots-jl-plotly-backend/73076 "2021-12-14T14:35:53Z")

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Hello, I am using Plots.jl with a plotly() backend and I am trying to plot more than one contour plot in the same figure with their respective color bars, since are on different orders of magnitude. When I try the code…

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## [Pluto inside Docker container](https://discourse.julialang.org/t/pluto-inside-docker-container/46386)

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**Author:** [@Vadim\_Lebedev](https://discourse.julialang.org/u/Vadim_Lebedev)\
**Replies:** 5\
**Last updated:** [December 14, 2021, 2:11pm UTC](https://discourse.julialang.org/t/pluto-inside-docker-container/46386 "2021-12-14T14:11:07Z")

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I’m running julia inside docker container, i’m unable to expose Pluto listening port 1234 to my host because Pluto binds to 127.0.0.1:1234 I need it to bind to 0:0.0.0:1234 Any advice?

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## [User MIP start did not produce a new incumbent solution](https://discourse.julialang.org/t/user-mip-start-did-not-produce-a-new-incumbent-solution/72269)

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**Author:** [@ZHEN\_LIN](https://discourse.julialang.org/u/ZHEN_LIN)\
**Replies:** 5\
**Last updated:** [December 14, 2021, 1:57pm UTC](https://discourse.julialang.org/t/user-mip-start-did-not-produce-a-new-incumbent-solution/72269 "2021-12-14T13:57:09Z")

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I have a mixed integer optimization to be solved with Gurobi in JuMP. I am trying to give a warm start to Gurobi, but it gives me the following message User MIP start did not produce a new incumbent solution Processed M…

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## [Translating Binomial N-mixture models from Jags](https://discourse.julialang.org/t/translating-binomial-n-mixture-models-from-jags/72579)

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**Author:** [@FolgertK](https://discourse.julialang.org/u/FolgertK)\
**Replies:** 8\
**Last updated:** [December 14, 2021, 1:50pm UTC](https://discourse.julialang.org/t/translating-binomial-n-mixture-models-from-jags/72579 "2021-12-14T13:50:31Z")

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Hi there! I’m new to Julia and Turing, but I’m trying to translate some ecological models by Kéry and Royle (2016) from JAGS to Turing. The specific model here is a Binomial N-mixture model (or a Poisson-Binomal mixture…

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## [Count various patterns simultaneously](https://discourse.julialang.org/t/count-various-patterns-simultaneously/73066)

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**Author:** [@ludwig-austermann](https://discourse.julialang.org/u/ludwig-austermann)\
**Replies:** 5\
**Last updated:** [December 14, 2021, 1:34pm UTC](https://discourse.julialang.org/t/count-various-patterns-simultaneously/73066 "2021-12-14T13:34:10Z")

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I was just wondering if there is a nicer way to do practically this: reduce( (d, c) -\> (d\[c\] = get(d, c, 0) + 1; d), "ACCACD", init=Dict{Char, Int}() ) hence, to do a non-binary count s = "ACCACD" Dict( c =\> c…

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## [Solving quasi-linear heat diffusion using DiffEqTools.jl and DifferentialEquations.jl](https://discourse.julialang.org/t/solving-quasi-linear-heat-diffusion-using-diffeqtools-jl-and-differentialequations-jl/72954)

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**Author:** [@Iddingsite](https://discourse.julialang.org/u/Iddingsite)\
**Replies:** 2\
**Last updated:** [December 14, 2021, 1:31pm UTC](https://discourse.julialang.org/t/solving-quasi-linear-heat-diffusion-using-diffeqtools-jl-and-differentialequations-jl/72954 "2021-12-14T13:31:52Z")

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Hi everyone. I am new to Julia and decided to give a try to the SciML framework. My goal is first to solve the quasi-linear heat equation using the method of Lines. \\partial\_t T = \\partial\_x (\\kappa(x) \\,\\, \\partial\_…

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## [How to count all unique character frequency in a string?](https://discourse.julialang.org/t/how-to-count-all-unique-character-frequency-in-a-string/19342)

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**Author:** [@orange\_si](https://discourse.julialang.org/u/orange_si)\
**Replies:** 25\
**Last updated:** [January 8, 2019, 12:50am UTC](https://discourse.julialang.org/t/how-to-count-all-unique-character-frequency-in-a-string/19342 "2019-01-08T00:50:54Z")

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Hello everyone, Is there a function build-in julia to count all unique character frequency in a string? I seemingly saw it before some days ago, but I cann’t remember that and cann’t fount it in the doc. Thanks~ Regar…

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## [How to understand Makie.jl functions signatures](https://discourse.julialang.org/t/how-to-understand-makie-jl-functions-signatures/53157)

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**Author:** [@akalinin](https://discourse.julialang.org/u/akalinin)\
**Replies:** 5\
**Last updated:** [December 14, 2021, 12:03pm UTC](https://discourse.julialang.org/t/how-to-understand-makie-jl-functions-signatures/53157 "2021-12-14T12:03:43Z")

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I want to draw 3D mesh using Makie.jl. I try to inspect mesh function julia\> using GLMakie help?\> mesh mesh(x, y, z) mesh(mesh\_object) mesh(x, y, z, faces) mesh(xyz, faces) For me it is not clear what are th…

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## [Events on Julia](https://discourse.julialang.org/t/events-on-julia/73044)

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**Author:** [@cesarmarinhorj](https://discourse.julialang.org/u/cesarmarinhorj)\
**Replies:** 4\
**Last updated:** [December 13, 2021, 11:07pm UTC](https://discourse.julialang.org/t/events-on-julia/73044 "2021-12-13T23:07:06Z")

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Julia has something like Events? “on” → “event” → callback thanks!

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